Forgive me if this has been covered here...

Customer requires all users of a certain type to provide SSN. These users
come and go from the organization, but their accounts are retained in the
IDVault. Customer wants to avoid duplicate account/record creation...

so,

I want to develop a process such that the first step of the workflow
involves entering Given Name, Surname, and SSN. The initiator then submits
the request and it self-assigns to the initiator as the recipient.
Meanwhile the process queries the tree, and when the initiator goes to
handle the workflow, it is pre-filled with data from any discovered matching
object.

1. Is such a pre-create validation scenario possible? Ideally the workflow
would query the tree, and if it finds a user with a matching SSN, it would
pre-populate the remaining forms with data from the existing user.

2. Is there an easier way, so that I could combine both functions on a
single page?
I'm just learning the possibilities here, but could I have SSN be the
first field on the page, and then have an "onchange" event do a query of the
tree which would populate all remaining fields with data in the event there
is a match to the query?
What problems do I run into, or need to avoid, in knowning that almost ALL
of these queries will come back empty?

Thanks for any insight.

Rob.